This disclosure relates to a hybrid antenna that includes a primary antenna element having concentric conductors. The primary antenna element is capacitively and inductively coupled to a secondary antenna element having parallel conductive radiating members. No direct electrical connection is made between the primary and secondary antenna elements. The primary antenna element has a physical length equal to a halfwave section for a selected frequency at its velocity factor. It is center fed. The physical length of the secondary antenna element can be one or more multiples of a halfwave length for the selected frequency, with one or more multiples of a quarter-wave length being arranged to each side of the midpoint of the primary antenna element. When desired, the primary antenna element can be encased and sealed within a tubular secondary antenna element.
The primary antenna element, which combines operational characteristics of a balun, a transformer, and a folded dipole antenna, can be constructed from any concentric conductor assembly having a continuous central conductor surrounded by a spaced outer concentric conductor. An example would be conventional coaxial cable, which might be either flexible line cable or an air-insulated line. The secondary antenna element can be produced from any electrically conductive material having the physical configuration of a wire, rod or tube. In the concentric configuration of the antenna, a suitable material for the secondary antenna element is a straight length of aluminum tubing.
There is no direct electrical connection between the primary and secondary antenna elements in this combination. By isolating the radiating conductor of the secondary antenna element from the primary element or transformer, the antenna has been found to exhibit exceptional ability to resonate over a wide range of frequencies without an appreciable change in the Standing Wave Ratio.
The antenna has been designed for commercial broadcast of reception usage over a broad range of frequencies, including marine, citizen's band and amateur applications.